Ted's Caving Page (also known as Ted the Caver in some parts of the internet) is a Web Serial Novel detailing the attempts of spelunker Ted and his two friends to explore a strange, undiscovered portion of a local cave. Ambiguous horror ensues.
First published on the Angelfire webhosting service in 2001, this story was an early example of using the Internet to tell a horror story Blair Witch-style, and remains pretty effective to this day. It can be found here.

Hell Is That Noise: An in-universe example. Says Ted of the mysterious scream, "I would say it sounded like a cross between a man screaming in fear, and a cougar screaming in pain".

I Don't Like the Sound of That Place: Invoked, as Ted names the passage that they discovered "Floyd's Tomb". As if that weren't ominous enough, it's named after caver Floyd Collins, who died after getting himself caved in.

Plagiarism: Inverted (?). A bizarre rumor spread after this story's popularity grew that it was stolen nearly word-for-word from a short story written by Thomas Lera called Fear of Darkness from the eighties. As it turns out, the story never existed until after Ted the Caver became widely known, and is simply Ted the Caver with the prose cleaned up to be a little more "scholarly" and a stereotypical ghost-story ending tacked on. Lots of people, sadly, bought it hook, line, and sinker.

Primal Fear: Go ahead, read the bit about being in total, pure darkness, and see if you don't get at least mildly creeped out.

Ultimate Evil: It's obvious that there's something down there that doesn't want to be disturbed, but what it is, we never find out. Ted briefly mentions an old myth regarding the Hodag, a creature that dwells in caves, but nothing much comes of that.